Current-collecting mechanism



M 1930. E. A. BINNEY 1,757,611

CURRENT COLLECT ING MECHANI SM Filed July 27, 1926 g ,lj' 4? m 1:

INV EN TOR.

r 5 I I 7 w M23 Patented May 6, 1930 UNITED srxrss PATENT. OFFICE- ERIC ALTON BINNEY, or saw mnoo, oanronnm CURRENT-COLLECTING mnomrsu Application filed July 27, 1926. Serial in. 125,304.

The invention relates to the brush and brush box, forming the sliding contact and stationary holder therefor of the current-collecting mechanism, such as used on electrical machinery. The sliding contact is herein referred to as the brush.

The objects of the improvement are to provide means for allowing undesired foreign matter to pass between the surface of the box 1 and brush without causing serious wear to either. To greatly increase the useful life of the brush to increase the life of the box; to ensure lasting good contact between the brush and box and to ensure lasting good contact between the brush and commutator.

It is well known to those familiar in the art, that the brush must be a close sliding fit in the brush box, it being usual to allow only a few thousandths of an inch clearance between the two members. Now it is found in practise that particles of foreign matter, such as fine sand and dust, drawn into a machine by the ventilating air, are likely to find their way between the brush and box, becoming wedged between the brush surface and inner box surface. The slight movement of the brush with respect to the box, caused by vibration, etc. causes the dust to act as an abrasive, while at the same time to work its way from one end of the box to the other. This results in very appreciable wear of the brush side surfaces, causing the clearance between brush and box to become excessive and necessitating the replacement of'the brush before its useful length has been used up. It is also found that the box surface becomes worn due to the same action, so that in time the box must be replaced.

To reduce the deleterious effect of the foreign matter, this invention provides a suitably prepared surface on the brush or on the inner box surface, or on both. This may be carried out in various Ways, examples of which are described and illustrated in this specification. In all cases a space of some form is provided between the actual contact surface of the brush and box, either by providing such spaces in the brush surface or the inner box surface or both. This space allows 50 the undesired matter to find a way out or remain trapped in such a manner asto prevent it from wearing the brush or box surface.

Figure 1 is a perspective view of a brush having grooved side surfaces, representing one method of treating the brush surface.

Figure 2 is a sectional plan view in the plane 1-1 in Figure Figure 3 is a fragmentary elevational view of a knurled brush; Figs. 3, 3 3 and 3 illustrate various modifications of brush surface treatment; Fig. 4 is a fragmentary sectional view of a knurled brush, while Figs. 4c,- 4", 4 and 4' represent fragmentary sectional views of the modifications illustrated in Figs. 3,

3", 3, and 3 respectively.

Figure 5 is an elevation of a brush box, partly in section, showing depressions and apertures in the inner surfaces and through the walls of the box. I

Figure 6 is a plan view of the same box, while Figure 7 is the side elevation.

Describing now in detail the various illustrations, in Figures 1 and 2 the brush 11 has side surfaces 12, 12 and 13, 13 and end surfaces 14, 14. The four side surfaces are provided with a plurality of grooves or depressions 15 and 15 The grooves 15 commence at the central, vertical groove 15 in the surfaces 12, 12, and run outwardly and downwardly at an angle of approximately 60 degrees to the end surfaces. In the side surfaces 13, 13 grooves 15 are shown running from one side to the other at an angle of about 60 degrees to the end surfaces. It is however, not intended to infer that any one arrangement of grooves is best for all sizes of brushes, the system illustrated in Figure 1 merely being a preferred arrangement for a brush of the relative dimensions chosen in this instance.

In Fig. 2, which is a cross section through the brush 11 in a plane 1-1 parallel to the end surfaces, the disposition of the grooves 15, 15 and 15 is clearly shown. Itis seen that the surfaces 12 and 13 are reduced to the area represented by the various ribs or teeth 16, 16, the total area of which is, of course, a greater or less percentage of the plane surfaces 12, 12 and 13, 13. These ribs or teeth form the actual contact surface of brush and box, while the depressions or grooves provide 100 the space for allowing the foreign matter to pass throiwh without seriously wearing the contact surfaces 16, 16.

In Figs. 3, 3", 3 and 3 various modifications of patterns of depressions that may be formed in the brush surfaces are shown. The portion designated (a) is represented as having a plurality of cavitiesor pockets 17, 17 formed in the otherwise level surface (a). The portion (6) contains a checker pattern system of depressions 18, 19, leaving the squares 20 to form the contact surface. In the portion (a) the depressions 21 are wave shape while in (d) a pattern of narrow, vertical grooves 22 is shown.

Figure 3 shows an enlarged fragmentary elevational view of a brush-having a knurled surface formed by a large number of small substantially V-shapegrooves 36, see Fig. 4, extending lengthwise with the brush, and forming interspersed ridges 37. The grooves are relatively shallow and close together, and the side surface formed is consequently made up ofa large number of very narrow, practically linear strips occupying a common lane,

The sectional views Figs. 4*, 4, 4, and 4, correspond to the fragmentary elevational view of Figs. 3 3 3, and 3 respectively.

The number and depth of the grooves or cavities may be varied within certain practical limits. In general, it is desirable to provide a relatively large number, placing them close together, so that the sand grains have not far to travel before reaching a depression into which they may fall. The knurled type of surfacing may also be carried out by providing a second intersecting series of grooves, similar to the pattern illustrated in Fig. 3", the resultant raised portions forming substantially pyramidal beads.

Figures 5, 6 and 7 illustrate a brush box of conventional design, in which 30 is the box proper, 31 is a slot for allowing movement of a pressure finger, not shown, which normally exerts the necessary pressure on the top of the brush, arm 32 is shown in part only, depressions 33, 33 are in theinner surfaces of the brush box, vertical grooves 34:, 34 positioned in each inner corner of the brushbox 30, with which the depressions 33, 33 communicate and apertures 35, 35 penetrating the walls of the box 30.

If a suitably dimensioned, smooth surfaced brush, is placed in the box 30, it is obvious that the depressions 33 and apertures 35 will allow a foreign matter to pass between the brush and inner box surface without seriously wearing the brush or box contact surfaces. Thus, the same purpose is served whether the grooves or depressions are placed in the brush surfaces or the inner box surfaces. The important thing is to provide a space between contacting brush and box surfaces in which a foreign substance may be accommodated, and if desired, allowed to pass out from between the contiguous surfaces.

With a broad interpretation of this in mind I make the following claims:

1. In an electric current collecting brush mechanism, a brush member provided with a plurality of superficial depressions in its outer surface for eliminating deleterious matter.

2. In an electric current collecting brush mechanism including a brush-holder, a brush member provided with a plurality of superficial grooves longitudinally with its movement in its holder in its outer surface for the passage of deleterious matter.

3. In a brush holder mechanism for an elecric current collecting mechanism, a brush box, and a brush slidable longitudinally therein, the side surfaces of said brush forming with the contiguous inner box surfaces, a plurality of closely spaced contacting areas and a plurality of interspersed superficial channels between adjacent side edges of said brush for the release of deleterious matter between the contacting areas.

4. In a brush mechanism for a current collecting mechanism, a brush box, and a brush slidable longitudinally therein, some of the side surfaces of said brush having a plurality of superficial grooves therein extending substantially lengthwise along the brush, said grooves forming with the contiguous box surfaces, shallow passages between the contacting areas of the brush and box surfaces for the escape of deleterious matter.

5. In a brush mechanism for a current collecting mechanism, a brush box. and a brush capable of sliding longitudinally therein, a plurality of raised areas and a plurality of interspersed depressions formed in the inner surfaces of said box between adjacent side edges of said brush. said raised areas forming with the contiguous brush surfaces, contacting areas. said depressions forming with the contiguous brush surfaces, recesses for the escape of deleterious matter from the contacting areas.

6. In a brush mechanism for an electric current collecting mechanism, a brush box, and a brush capable of sliding longitudinally therein, a plurality of depressions formed in the inner surfaces of said box between ad-- group of grooves extending at an angle to i said first group and forming therewith substantially pyramidal beads in said surfaces.

8. In an electric brush mechanism, a brush of substantially prismatic form, the surfaces forming the sides thereof being knurled in the pattern of a multiplicity of longitudinally extending substantially V-shape alternate grooves and ridges.

9. In a brush mechanism, a brush member having a substantially prismatic form of rectangular section, certain of the side surfaces thereof having a plurality of parallel grooves extending from end to end of said brush, the depth of said grooves being slight in relation to the minor dimension of said rectangular section, said grooves forming channels for the passage of deleterious matter.

ERIC ALTON BINNEY. 

